The skeletal dysplasias are a heterogeneous group of disorders which result in disproportionate short stature and/or skeletal deformities. This study involves a multidisciplinary investigation of the clinical, genetic, morphologic, biochemical and molecular characteristics of the skeletal dysplasias. In the past year, these studies have resulted in the identification of the genes responsible for several dysplasias, including pseudoachondroplasia and achondrogenesis. In the future the GCRC will continue to assist in specimen collection for these molecular studies.